The invention relates to a centrifugal separator bowl for a nozzle separator developed for high solids applications, including those up to about 2.0 specific gravity (SG). The invention further relates to a centrifugal separator using such a bowl.
A centrifugal separator consists of several stationary as well as rotating components. The feed pipe directs the separator feed, a solid/liquid mixture with high specific gravity, to an accelerator which directs the mixture into the rotating bowl. While the feed pipe is stationary, the accelerator and the bowl may rotate. In the separator bowl, the separator feed is separated, due to rotational forces, into two fractions. These two fractions leave the separator bowl either through the (rotating) disc stack, (stationary) centripedal pump, and (stationary) discharge pipe, as the so-called overflow, or through the nozzles at the outer bowl wall and the (stationary) cyclone, as the so-called underflow. Due to the rotational forces inside the bowl, the lighter fraction (lower specific gravity) is following the overflow path while the heavier fraction (higher specific gravity) is following the underflow path.
Centrifugal separators as they exist in the current state of the art, when provided with a feed of a mixture of high specific gravity, e.g., mineral suspensions up to 70% solids content, face the risk of material build-up in the bowl. This can result in machine vibration or, by exceeding the material strength of standard bowl material (e.g., duplex steel), a material failure.
Existing centrifugal bowls are manufactured in multiple parts or have separate inserts for directing the flow of the suspension to the nozzle openings. When a centrifuge operates at high speeds, such a split bowl may break apart. If there are inserts in the bowl, these may loosen during operation and may block openings. Loosened inserts may even lead to a break in the bowl, due to potential instability and increased vibrations from the unbalanced weight.